The present invention relates to rear view mirror assemblies, such as those used in automobiles, and, in particular, to rear view mirror assemblies which provide high reflectivity position and low reflectivity position for night time conditions.
Many conventional rear view mirror assemblies employ prismatic mirrors which can be positioned by the vehicle operator in a high reflectivity or low reflectivity disposition. Such prismatic mirrors can be movably driven by a mechanical actuator mounted, for example, on the housing of the mirror assembly, or by an electronic circuit having a motor or solenoid driven actuator to manipulate the mirror or mirror/housing combination between the low and high reflectivity dispositions.
For example, U.S. Pat. No. 4,443,057, which issued to Bauer et al., discloses an automobile rear view mirror whose housing is moved by an eccentric cam driven by a uni-directional DC motor. As is disclosed in the above-identified Bauer et al. patent, the energization of the DC motor is controlled by limit switches, which switches sense when the mirror is in the low and high reflectivity dispositions. The limit switches cut off current to the DC motor. The use of limit switches is typical of many conventional automotive rear view mirror assemblies.
There are numerous inherent disadvantages associated with the use of limit switches. First, the housing of the rear view mirror provides limited space for carrying the electronic circuitry and mechanical structure associated with moving the mirror between the low and high reflectivity dispositions. A pair of limit switches usually require associated gearing, camming or other structure to actuate the switches, and such structure takes up an inordinate amount of space. Second, the mechanisms used for actuating and mounting the switches are relatively complex, making assembly and repair of the rear view mirror assembly difficult and time consuming.
Another disclosed mechanism in U.S. Pat. No. 3,680,951 to Jordan, et al. is a photoelectronically controlled rear view mirror which includes a first photocell to switch the mirror between "normal" and "adjusted" positions in response to incident light on the mirror, and a second photocell to monitor ambient light thereby preventing switching of the mirror to the "adjusted" position during daylight hours and at night where high ambient light conditions exist. Jordan, et al. utilize a pair of permanent magnets in combination with an electromagnet therebetween in which polarity can be alternated to drive a cam back and forth, which, in turn, moves a projection bearing thereagainst in order to adjust a mirror between positions of high and low reflectivity. The solenoid of Jordan, et al. must be continually energized to maintain the mirror in the desired orientation, and the cam/cam follower combination does not provide a smooth transition between the different reflectivity positions.
Other disclosures for mechanically changing the reflectivity orientation of rear view mirrors variously include electromagnetic means and pivotal base mounted mirrors, etc. However, it has become continuously clear that a smooth-operating two-position rear view mirror is required for automobiles in order to provide smooth and dependable switching for conditions of high and low ambient light.
Thus, it is an object of the present invention to provide a rear view mirror assembly which can be efficiently manufactured to provide smooth and dependable switching between positions of high and low reflectivity.
Another object of this invention is to provide a mechanical drive for smooth continuous movement of the mirror by use of a dependable bi-directional D.C. motor.
It is also an object of the present invention to provide an electronic control circuit for a motor driven, rear view mirror assembly.
It is another object of the present invention to provide a motor control circuit for a rear view mirror assembly which eliminates the need for limit switches.
It is a further object of the present invention to provide a control circuit for an automobile rear view mirror assembly, which control circuit is relatively simple and reliable and takes up relatively little space in the housing of the rear view mirror assembly.
It is yet another object of the present invention to provide a mirror control circuit for an automobile rear view mirror assembly which overcomes the inherent disadvantages of conventional rear view mirror assemblies.
It is further object of the present invention to provide a push-button switch, actuatable by the vehicle operator to change the reflectivity of the mirror, which switch is easy to manufacture and to assemble.
It is another object of the present invention to provide a push-button switch for a rear view mirror assembly which can be actuated with slight pressure.
It is a further object of the present invention to provide a push-button switch whose housing may be economically formed from identical molded half housing members.
It is yet another object of the present invention to provide a contact assembly for an electrical switch, which contact assembly is responsive to slight actuation pressure to provide an electrical path through the switch.
It is yet another object of the present invention to provide a contact assembly for an electrical switch which can be easily fabricated.
It is a still further object of the present invention to provide a push-button switch which has few components.